Writing instrument



FIG. 1 is a front elevational view of a writing instrument showing my new design thereof;

FIG. 2 is a right side elevational view, left side being a mirror image thereof;

FIG. 3 is an elevational view of the pen body in an exploded condition, with the cap member removed for convenience of illustration, all sides being identical thereof;

FIG. 4 is a bottom plan view of FIG. 3 thereof;

FIG. 5 is a front elevational view of the pen cap with the pen body removed for convenience of illustration thereof;

FIG. 6 is a right side elevational view of FIG. 5, the left side being a mirror image thereof; and,

FIG. 7 is a top plan view of FIG. 5. 

The ornamental design for a "writing instrument", as shown and described. 